Size reduction of Ge-on-Si photodetectors via a photonic bandgap

摘要

This work shrinks down the size of Ge-on-Si photodetectors to reduce the dark current and maintain the optical responsivity by surrounding photonic crystals. Numerical simulation shows that the employment of photonic crystal in the Si slab effectively prohibits the radiation modes from those guided outgoing waves and facilitates light cyclic absorption in the epitaxial Ge region. A photodetector with a 5 mu m long Ge absorption region is demonstrated with a dark current of 150 nA (1 mu A up to 70 degrees C), a 3 dB bandwidth of 17 GHz, and a responsivity of 0.75 A/W. (C) 2018 Optical Society of America